Guard for presses, stamps, and like machines



Aug. 19, 1924. 1,505,467

H. D. JACKSON GUARD FOR PRESSES STAMPS, AND LIKE MACHINES Filed March21. 1923 2 Sheets-Sheet 1 H. D. JACKSON GUARD FOR PRESSES. STAMPS, ANDLI'KE MACHINES Filed March 21 192B 2 Sheets-Sheet z ill Patented Aug,19, 1924 r/[Ttr orn ce.

HERBERT DAVID Jackson, 0F WAIiSALL, ENGLAND.

GUARD FOR PRESSES, STAMPS, AND LIKE MACHINES.

Application filed March 21, 1923. Serial No."626,588.

This invention relates to improvements in guards for power presses,stamps, and like tools, and refers particularly to an improved guardwhich is adapted to obviate any possibility of injury to the operatorduring 'a working stroke of the press or the like.

In the usual type of press or stamp a pulley is continuously driven bybelting or like means and is temporarily clutched to the cross shaftwhich carries the pressoperating eccentric or like means by a key orother clutch which 'is thrown into engagement when a lever is depressedby the operator.

A fixed guard is generally provided on the left of the tools or dies sothat the operator must place the blank upon thefixed die with the righthand which is also used for depressing the lever, and in theory safetyis thus obtained since the lever cannot be depressed while theoperatorsfingers are between the dies.

It has also been proposed to provide a sliding guard which is moved intoposition in front of the dies when the lever is depressed, but both ofthese methods fail to guard against the possibility of defectsdeveloping in the clutch mechanism, or of the press being given twoworking strokes for one depression of the lever either through theclutch key'becoming worn, or

through backlash developing in the-lever mechanism, and as the guard inthe latter case only protects the dies when the lever is depressedinjury to the operator may easily occur.

Guards have also been proposed which are brought into operation by themoving die as it descends on its working stroke, but such guards do notcome into the full operative position until the die has moved aconsiderable distance, and also, owing to the rapid motion of the die,the movement of the guard itself is rapid and may cause injury to thefingers of the operator.

The object of 'my invention is to provide an improved guard for powerpresses, stamps and like machines, in which the guard is independent ofthe clutch or operating lever, and is positively brought into action bythe rotation of the cross shaftso that the moving die cannot descendwithout being protected by the guard, and the'possibility of accidentalinjury to the operator is, eliminated.

A further object of my invention is to provide a guard which is broughtinto its active position before the moving diefhas travelled anappreciable distance on its working stroke and which protects thediesuntil the moving die is near the end OfltS return stroke. 1 1

This is particularly important for drawing dies where the moving dieentersa con siderable distance into the fixed die and the clearancebetween the dies inflthe inoperative position is not great. 5

With these objects in view my invention essentially comprises a guardfor power presses, stamps, and like machines, in which a guard memberadapted to protect the tools or dies during the working. stroke iscarried by a reciprocating member which is slidably mounted on the bedofthe press or the like and is moved into the operative position by alever and cam mechanism from the cross or driving shaftof the press asthe movable die begins its working stroke and is withdrawn by a springas the diereaches the end of its return stroke, the striking face of thecam: being arranged at such an anglethat the guard is moved into thefully operative position before the die has moved an appreciabledistance on the working v stroke. I I

My improved guardmay'be arranged in a variety of ways to adapt itforuseon different types of presses, butone preferred embodiment, whichis suitable for a variety of presses, has been illustratedbywway ofexample in the accompanying drawings in which Figure 1 is a plan of theguard operating mechanism showing the guard in its retracted position infull lines and in the forward, or operative position in dotted lines.

Figure 2, is a front elevation.

Figure 8, is a diagrammatic end elevation of the complete guard showingthe lever and cam mechanism.

Figure 4, is a diagrammatic front elevation showing, in full and dottedlines respectively, the guard in the retracted and operative positionsrelative to the dies.

In the. drawings a is the guard member which. may conveniently beformedof sheet metal of a suitable size and shape corresponding to thedies with which it is used, and having its forward end curved round asshown at a in Fig. 1 to prevent injury to the operators hand if theguard should come into contact with it.

The guard is secured by bolts 6 to a rectangular reciprocating member 0which is slidably mounted between and guided by three pairs of verticalrollers d upon a base plate 0 secured to the bed of the press by boltse.

The'member 0 is horizontally slotted for a portion of its length asshown; at c" and within this slot is housed a flat slide cam or wedgemember f of substantially triangular outline as shown in Fig. 1. Therear edge of the member f is at right angles to the reciprocating member0 and bears against one pair of therollers cl, while the front edge isinclined at an angle of, say, 45 and, bears against a roller g'carriedon a vertical pivot at the forward end of the slot 0. A tension spring his connected between a pin j on the reciprocatingmember c and a pin 70on the bridge piece for the outer pair of rollers (Z or any otherconvenient fixed point and serves to retain the member 0 normally in theretracted position shown in full lines in Fig. 1.

The member f has an integral boss 7' into which is screwed one end of ahorizontal rod Z atthe other end of which is a forked head m withinwhich is pivoted the lower end of a substantially vertical lever 91.This lever is pivoted at 19 upon the frame of the press and carries atits upper end roller q engagmg a cam 1' on the cross or driving shaft Asof the press. The cam. is preferably of an outline substantially similarto that illustrated in Fig. 3, and is keyed upon the shaft .9 in such aposition relative to the crank or eccentric by which the moving die ofthe press or eccentric is reciprocated that the ca m lifts the roller gand'moves the upper end of the lever n outwards 'as the crank oreccentric moves over top dead centre on the working stroke, and as themovement of at the upper limit of its movement on the return stroke thedies are covered by the guard.

The action of the device will be readily followed from the drawings.

As the moving die approaches the upper limit of its movement on-thereturn stroke the roller 9 rides ofi the cam 7' and the wedge member ftogether with the rod Z and the lower end of the lever 12 is free tomoveto the right in Fig. 3 under the influence of the spring h whichretracts the member 0 and with it the guard a into the position shown infull lines in Fig. 4. The dies t are thus uncovered and blank can beplaced in position on the fixed die. When the press clutch is engagedand the shaft 8 commences to rotate, the cam engages the roller 9 androcks the lever a about its pivot so that the lower end of the lever iscarried to the left in Fig. 3 taking with it the rod Z and the wedgemember f which in turn moves the reciprocating member 0 forward to bringthe guard into the operative position as shown in dotted lines in Fig.a. All danger of the operators fingers being trapped be tween the diesis therefore eliminated. Small bolts and washers a may be provided onthe edge of the wedge member f parallel to the reciprocating member 0to, formastop for the member f and prevent it from being completelywithdrawn from the slot in the member 0 by a too violent actuation ofthe lever a, but these are not essential in all cases.

I claim: 1. A guard for power-presses, stamps, and-like machines,comprising a guidedreciprocating member, a guard member carried by thesaid reciprocating member, resilient means for retaining thereciprocating member normally in the inoperative posimember, a guardmember carried by the-said reciprocating member, a base plate, pairs offixed rollers .on the saidwbase plate between which rollers the sa1dreciprocating member is slidably guided, a wedge member of substantiallytriangular outline adapted to slide in a slot in the reciprocatingmember and abutting between one pair of fixed rollers and a roller atone'end of the slot, a-lever pivoted upon the frame of themachine, a

horizontal rod connecting the lowerend of the said lever to the saidwedge member, a

machine, and a spring which effects the return movement of thereciprocating member. In testimony whereof I aifix my signature.

HERBERT DAVID JACKSON.

